1. Field of the Invention
This invention relates generally to a mechanical hand held door opener device, light in weight and operable in any orientation, including inverted, for generating a substantial door-opening force with a minimum effort from the user. More particularly, this invention is referred to as a mechanically-operated hand-held forcible entry device, capable of providing a set of useful features for firefighters and law enforcement agents using a simple mechanical device.
2. Description of the Prior Art
Forcible entry is a technique used to gain access to a structure whose normal means of access is locked, blocked, or nonexistent.
There are several situations in which a forcible entry is required. Some of the most common are: rescue, escape, fire, preventing further property loss, accessing areas critical to pass through, etc. Every different forcible entry always involves forcing a door or a window for which different type of tools are used.
Depending on the physical structure and function, the tools used during a forcible entry may be classified as: striking tools, prying tools, hydraulic tools, lock pulling tools and cutting tools, among others.
Among the striking tools, the following may be named: flat-head axe, sledgehammer, battering rams, hammers, and duck-billed lock breaker.
The flat-head axe, whose primary use is for breaking down doors, comprises a chrome-plated or steel flat head with a wooden or plastic handle. Heavy enough for a short strike stroke on an iron or padlock breaker, its large oversized head makes the strike stroke zone more accurate and easy to hit. Its cutting edge is usually annealed to keep its edge longer.
A sledgehammer, comprising a large, flat head attached to a handle, can apply a great impulse due to its large size and distribute force over a wide area. This tool is commonly used by police forces in raids on property to gain entry by force, commonly through doors.
Battering rams, comprising a large heavy metal ram carried by two people and propelled with force against an obstacle, are commonly used by SWAT teams for opening locked doors and effecting a forced entry. Other modern battering rams include a cylinder in which a piston gets fired automatically upon impact, which enhances the momentum of the impact significantly.
Hammers are also used as a smaller version of sledgehammers, and they are especially useful for weak wooden doors or windows.
A duck-billed lock breaker is an all steel tapered head designed to be placed in the shackle of a padlock and when hit with a mallet or the back of an axe easily spreads the shackle open.
Regarding the prying tools we can mention: the Halligan bar, the adz bar and the pry bar.
The Halligan bar is a special tool commonly used in the fire and rescue service. The Halligan is a multipurpose prying tool consisting of a claw (or fork), a blade, and a pick, which is especially useful in quickly breaking through many types of locked doors. The fork end of the tool can be used to break in through an outward swinging door by forcing the tool between the door and door jamb and prying the two apart. Along with the K-tool and the adz or fork end a lock can easily be pulled. There are many other uses of the Halligan tool, including vehicle rescue and opening of walls. A Halligan bar and an axe can be joined together to form what is known as a married set, or set of irons.
The adz bar is a tool for all operations from forcible entry, to search and overhaul. This tool is a Halligan tool, except that an adz replaces the traditional fork on the end of the bar. The adz is gently curved and thin enough to penetrate those tight spaces during forcible entry operations.
The pry bar or more informally a jimmy bar, or gooseneck is a tool comprising a metal bar with a single curved end and flattened points, often with a small fissure on one or both ends. It is used as a lever to either force apart two objects or remove nails. A common use for larger crowbars is for prying apart boards, and generally smashing things. Crowbars can be used as any of the three lever classes but the curved end is usually used as a first-class lever, and the flat end as a 2nd class lever. Among the hydraulic tools, the following examples can be mentioned: the Rabbit Tool, the Port-A-Power and other powered tools.
Commercially known as the rabbit tool, this is a one piece integrated hydraulic forcible entry tool comprising an 11 lb., 13-inch long unit for cutting locks, bars and locking devices. It has stainless steel jaws with a spreading force and cutting force of 8,000 lbs. and features ¼″ teeth that allow for easy placement between a door and its jamb. Using the hand operated pump, the Rabbit can spread a door 4″ in 20-30 seconds.
Commercially known as the Port-A-Power, this is a portable pump unit associated with a 10 T hydraulic ram capable of creating a huge slamming force against any type of entries.
Another powered tool known in the art comprises an airless hand held hydraulic pump unaffected by gravity that continuously maintains pressure on the fluid in a dynamic reservoir chamber to enable pumping into a dynamic pressure chamber for actuating a forcing rod irrespective of the orientation of the pump. A release valve permits fluid return from the pressure chamber into the reservoir chamber. The pump can be fitted with a tool such as a door forcer.
The manual tools described above are useful for helping the firefighters and law enforcement agents to open weak doors, which can be opened using a regular lever or slamming force, but they are useless for opening strong doors. Instead, the hydraulic devices mentioned above are useful for opening strong doors, however they present the following drawbacks:
Hydraulic units create major problems by usually blowing out O-ring seals. Major leaks of oil create a dangerous spreading of toxic chemicals to the environment as well as the emission of fumes into the air. Furthermore, an extreme explosive surge is also created when seals are blown under pressure;
Secondary cylinders and hoses are required;
Hydraulics cannot be inverted with usage;
In most cases the door is ruined after it is opened;
Because of the internal fluids used in its hydraulic circuit, it cannot operate under extreme weather conditions;
They require excessive regular maintenance when is not being used.
Pneumatic devices including an inner air pressurized container are another known solution in the market. These are similar to the hydraulic ones, with the following drawbacks:
Limited time use;
Require filtering of air;
Difficult to control the movement of components using air;
Pressurized gas being extremely dangerous for use in hot or cold environments;
Constant and heavy maintenance.
Heavy carrying accessory chargers.
Therefore, a reliable fully-mechanical forcible entry device capable of avoiding the above-mentioned problems with a simple, low-maintenance and economical structure is still desired.